This project has as its overall objective the study of the chemical constituents of human colostrum and breast milk and their potential significance to infant nutrition and development. We will define 1) trace metal (Zn, Cu, Cr, Mn, Co, Ni, Mo) concentration (free and metallo-peptide (carrier) complexes), by atomic absorption spectrophotometry, gel chromatography and ultrafiltration; 2) determine the presence, physical and chemical properties, amino acid composition and sequence of low molecular weight polypeptides (m.w. less than or equal to 14,000); and quantitate the naturally occurring polyamines and determine the existence of polyamine-peptide conjugates. We will evaluate the possibility of the general existence of specific trace element and other carrier molecules which facilitate bioavailability of these substances to the neonate. Stability and temporal changes of peptides as a function of lactation time will be investigated. Fractionation of milk will be accomplished by gel chromatography of ion exchange chromatography and their purity assessed by two dimensional chromatography, analytical gel filtration, electrophoresis and N-terminal analysis.